"urban" what?

I was at primary school in a drawing class. But how to explain what it is about what we do passionately in front of 23 kids? Not that easy as they won't understand you as soon as you use expressions as "urban". So I tried to draw what I was talking about (as you would recognize on the black board). No camera but a pen. Not a second but about an hour for capturing an image. Sitting somewhere drawing houses and people etc. But how great to watch as the draw themselves. They just went for it. And the chair that we drawed all together was not that easy, most did it better than I had expected at their age ...